JPS58183754A - Water absorbing resin composition - Google Patents

Abstract

PURPOSE:A resin composition, prepared by incorporating a powdery water- insoluble and water absorbing resin with a specific amount of a polyhydric alcohol, and capable of promoting the uniform permeation of water and exhibiting a remarkably high water absorption rate. CONSTITUTION:A water absorbing resin composition prepared by incorporating (A) a powdery water-insoluble and water absorbing resin, e.g. a water-insoluble hydrophilic crosslinked polymer obtained by polymerizing a water-soluble monomer and/or a monomer made soluble in water by the hydrolysis, a polysaccharide and a crosslinking agent, and if necessary hydrolyzing the resultant polymer with (B) 0.001-5wt%, preferably 0.01-2wt%, based on the component (A), bi--octavalent polyhydric alcohol and/or oxyalkylene ether thereof, preferably bi--trivalent for the former and bi--tetravalent for the latter. Ethylene glycol, propylene glycol, glycerol and an ethylene oxide (EO) or propylene oxide (PO) adduct thereof having <=2,000cP viscosity at 25 deg.C is preferably used as the component (B).

Description

[Detailed description of the invention] The present invention relates to a water absorbent resin composition.

Furthermore, the present invention relates to a powdery water-insoluble water-absorbing resin composition having an improved water absorption rate and having a high water absorption rate.

In recent years, saponified products such as cross-linked polyethylene oxide, cross-linked poval, self-cross-linked polyacrylic acid metal salts, and saponified products of cross-linked starch-acrylonitrile λ soft polymers have been used in sanitary products, paper diapers, etc. with relatively high absorption rJ and 11L cracks. Water-absorbing materials have begun to appear. However, although these materials have a high water absorption capacity, they are not sufficiently satisfactory for use in sanitary products, paper t-shirts, diapers, etc., which require a high water absorption rate.

In other words, the ability to absorb water? The higher the temperature, the stronger the affinity with water, so if these materials come into contact with water, gelation occurs only in the contact area, which prevents water from permeating uniformly, increasing the rate of water absorption. There was a problem that I could not get it. In order to improve this deficiency, a method has been proposed to increase the water absorption rate by pulverizing the water absorbing material to increase its surface area and increasing the contact area with water. . in this case,
Although the water absorption rate increases somewhat due to the increase in the area of the water-absorbing material, the essential water absorption rate decreases because a film is formed on the surface of the particles and a film is formed at the water contact area, preventing uniform water penetration. It didn't lead to any improvements.

The present inventors aim to improve these drawbacks, that is, to promote uniform penetration of water and to improve the water absorption rate. With the aim of obtaining a powdered water-inert water-absorbing resin, the present invention was achieved as a result of extensive research.

That is, the present invention consists of a water-insoluble water-absorbing resin (I) and a polyhydric alcohol compound/- or its oxyalkylene needle (m), and the amount of (m is 0 compared to the amount of (■)).
01 to 511 (powdered water-insoluble water-absorbing resin compositions with improved water absorption rate t', which are all characterized by being quantitative).

Examples of polyhydric alcohols used in the present invention include glycols such as ethylene glycol and propylene glycol; 1-liols such as glycerin, trimethylolpropane, hexanetriol, and triethanolamine; and mixtures of two or more of these. I'm going to give it a try. Preferred among these are ethylene glycol, ) propylene glycol 2 and glycerin.

Oxylated alkylene ethers of polyhydric alcohols, such as glycols such as ethylene glycol and propylene glycol; triols such as glycerin, trimethylolpropane, hexanetriol, and triethanolamine; pentaerythritol, diglycerin, and methyl Examples include tetonols such as glucosides; hexaols such as sorbitol; ophtols such as monosaccharides, and alkylene oxide adducts of mixtures of two or more of these.

As the alkylene oxide, aldo A-lene oxide having 2 to 4 carbon atoms [ethylene oxide (KO),
I pyrene oxide (PO), butylene oxide (1,2
-, 1,8-, 2,8-, 1,4-)], substituted products thereof (styrene oxide, etc.) 2, and two or more compounds thereof. Alkylene oxide addition 4' using two types of 1'l'' 2 compounds together! If Q k mru,
It may be a random addition or a block addition. Preferred among the alkylene oxides above
Combination system of EQ, PO and EO2['() (block,
random).

'+ (In JLK's terms, alcohol is ethylene glycol, triethylene glycol, polyethylene glycol EΔ1z equal molecular weight 1.1: (hereinafter referred to as MW toy')): 2 0 0.
ao O+400, 600.1000, etc.], polypropylene glycol (MW, 200., 400, 1
000.

2000, 4000, etc.), polypropylene resin (MW: 2400.
8 1 0 0.

4000, etc.), glycerin Poi・1 additive (MW:
400, 600, 1000, 8000.4000, etc.)
, Glycerin Eo (5 0) / PO (5 0) random adduct (MW: 2600, etc.), Ri-1 Nocerin P () (80) Kn (20) block adduct (MW:
3000, etc.), Torimechiro
Le Bro Nogun Pa (90)・Fl:o (10
) Block adduct (MW: 4500),) Limethylolpronokun P(l)
Nato), Hen lZx +J for S1--le PO(・1
Additives (MW: 600, etc.), Soleville Leur P (>
adducts (such as MW Nia 00), sucrose-glycerin mixture P (, 7Jll products with l (OH f + lli45
0) etc.

In addition, in the above, glycerin P (1 (80) EO (20
) Fluosoc adduct is L' (1 8
9% by weight total addition, and then 8020% by weight (all weights refer to total alkylene oxide) are shown.
) Random adduct is a random adduct of a mixture of t:050% by weight of glycerin and 50% by weight of PO.
Also, the weight percent indicates the total alkyleneoxy I11 (sub).

Oxia with many one song albums! Among the requilene ethers, preferred are polyethylene glycol, polyl-ropyrene glycol, PO adduct of glycerin, chrycerin-E O / PO random adduct, and Chryserif P.
O-E O block adducts, two-stage polypropylene glycol-EO adducts, and particularly preferred are polyethylene glycol, glycerin E (,1,/
, PO random adduct, glycerin-PO-1!
: (2-block adduct polypropylene glycol: 1
- RuE is an O adduct.

The q' average weight of the oxyalkylene ether of the polyhydric alcohol is usually 100 or more (preferably 200 or more - particularly preferably 400 or more), and usually 6,000 or more. The average molecular weight is EO of the polyhydric alcohol (in the case of additives, it is usually 1000 or more (preferably 600 or less),
In the case of PO adducts of polyhydric alcohols, the polyhydric value is usually 4000 or less (preferably 3000 or less), polyhydric 7 /L/]
-# (7) E (In the case of 1 and P 0 O combined adducts, it is usually 60oF or more (preferably 4500 or less). The average temperature of oxyalkylene ether of polyhydric alcohol is - If the amount becomes smaller than 6000, other problems such as poor powder flowability and caking occur. It is preferable 7
〈 is 2 to 311111 in the case of polyhydric alcohol,
In the case of the oxyalkylene ether, it is divalent to tetravalent. If (11) is more than octavalent, there will be other problems such as poor powder fluidity and occurrence of caking.

Among polyhydric alcohols and their oxyalkylene ethers, the latter are preferred.

-Also, it is preferable that the polyhydric alcohol and/or its oxyalkylene ether (Gl) be in liquid form.

Its viscosity (25C) is less than 8000 cps, especially 4 (
:2000cps or less is preferable. For those which are not liquid and have a viscosity higher than 8000 cps, it is preferable to use polyhydric alcohols of 1st viscosity and/or their polyalkylene ethers or other solvents. Examples of the solvent include cellosolves, such as ethyl cellosolve.

In the present invention, the water-absorbing resin includes a water-soluble 14-mer P, a 111-mer that becomes water-soluble by hydrolysis (A), a polysaccharide (B), a crosslinker (C), and a polysaccharide (B). A water-soluble water-absorbing resin is obtained by polymerizing it as an essential component and, if necessary, hydrolyzing it.

Among these, resins (water-insoluble/hydrophilic crosslinked polymers) obtained by polymerizing (A), (B), and (C) as essential components and hydrolyzing if necessary are preferred.

” 1 Used in the production of water absorbent resin (AL (B) 9
and (C) details 1, i), (B): ratio of b- and (C>, manufacturing method of water-absorbing resin, water absorption V1; 1 resin shellfish example is U.S. Pat. No. 4,076,668, Japanese Patent Publication No. 58 -4619
No. 9, Japanese Patent Publication No. 52-25886, Special Publication No. 51-462
It is described in No. 00. The water-absorbing resin used in the present invention has a water-absorbing performance of at least 60'm1. /f
(preferably 7omt7* or more"-1, especially 100 to 10
00 mt/l) is suitable.

1-Note (A) and (B) s, - Water-absorbing resins other than the resin obtained on the heavy stand of process (C) are (A) and (B).
For example, starch-acrylonitrile graft I'f (hydrolyzate of the combination, cellulose-
Hydrolyzate of acrylonitrile grafted vehicle, etc.; (
J(-polymer of A) and (C), such as polyacrylamide crosslinked with a divinyl compound (methylenebisacrylamide, etc.) and its partial hydrolyzate, crosslinked
Sulfonated polystyrene, crosslinked popal, crosslinked vinyl ester-unsaturated carboxylic acid copolymer saponified product crosslinked in JP-A-52-14689 and JP-A-52-27455 Polyacrylate and acrylic acid-acrylic ester copolymerization 11, crosslinked f'
Examples include isobutylene-maleic anhydride copolymer, two-process crosslinked polyethylene oxide, and the like. Furthermore, it has self-crosslinking properties (polymer of A"l, for example, Japanese Patent Publication No. 54
It is also possible to use the fνI resin described in Japanese Patent Publication No. 80710 and the high molecular weight polymer containing at least one hydroxyl group and one carboxylic acid group in the molecule, such as the resin described in Japanese Patent Publication No. 5487994. Two or more types of water-absorbing resins may be used.

The water-absorbing resin is in powder form (powder-like, two-particulate flake-like shape) and feels good when used.As such a powder-like water-absorbing resin,
A water-absorbing resin dried by a method (for example, J method using a drum dryer described in Japanese Patent Publication No. 55-21041)? A pulverizer (for example, Yoshito Izumi, etc.) is a complete crusher, turbo type, jet type, preferably 10 to 2000 microns.

The amount of polyhydric alcohol 2 or its oxyalkylene ether side applied to the powdered water-insoluble water absorbent resin (I) is α001 to 5% by weight, preferably α001 to 2% by weight. If it is less than 0,001% by weight (rDt), it is not much different from a water absorbent resin that does not contain rDt, and it is difficult to say that it is a water absorbent resin with improved water absorption rate. If it is more than 5% by weight, it is effective in improving the water absorption rate, but the water absorption performance is It is difficult to use it practically because other problems occur such as reduction in powder fluidity, poor powder fluidity, and occurrence of caking.

Powdered water-insoluble water-absorbing resin (I)? As a method for treating with polyhydric alcohol and/or its oxyalkylene ether (I), Φ) is added completely to (I), and a mechanical mixing device such as a Nauta mixer, ribbon mixer, conical blender, or mortar mixer is used. How to mix with,
Create a masterbatch in advance by adding CID to (1) at a high concentration (for example, 10 to 20%), and then add to masterbatch t to (I) so that the predetermined amount is added as ■. (I)
One method is to mix uniformly by spraying Tsukuda without stirring in a mixer. Alternatively, the mixture may be dissolved in a solvent such as methanol in advance and then treated with (I). Moreover, (2) may be added before pulverizing the water absorbent resin.

The powdered water-absorbing resin composition of the present invention contains fluidity aids such as finely powdered silica and talc; fillers, ultraviolet fire absorbers, oxidizing fire retardants, fungicides, bactericides, fragrances, colorants, etc. Other adjuvants may also be included.

The water absorbent resin composition of the present invention has various features. For example, (1) the water-absorbing resin composition of the present invention exhibits a high water absorption rate not only for water but also for human body exudates such as salt solutions, urine, and blood. For example, according to the water absorption rate measurement method described below, the time is usually improved to 178 times or less compared to conventional products (before treatment with @).

(2) The water absorbent resin composition of the present invention has fine particles (for example, 10
5 micrometers or less), water permeates uniformly without forming lumps in the water, and quickly becomes a water-absorbing gel.

(3) When the present composition is used to make products such as sanitary products and paper diapers, the powder is prevented from moving, scattering, falling off, settling, etc., and is immobilized.

The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto. Parts in Examples indicate parts by weight and weight %. In addition, the measurement of the water absorption rate in Example 2 was conducted by adding 50 d of physiological saline to a 100 d beaker.
After adding 2 tf of the water-absorbing resin while stirring and rotating with a magnetic stirrer, the time until the stirring bar stopped rotating was measured.

For permeability, put 2F4 of water-absorbing resin in a 50d beaker.
Subsequently, 80 d't of physiological saline was added gently to prevent the water-absorbing resin from dispersing, and the state of penetration into the interior of the water-absorbing resin was visually determined. The judgment criteria are as follows.

◎: No mamaco formation, good permeability ○: Good permeability, but some mamaco formation Subsequently, 80% of physiological saline was gently added to prevent the water-absorbing resin from dispersing, and the time until the whole gelatinized and the fluidity disappeared was measured.

Comparative Example 1 According to the method of Example 1 of Japanese Patent Publication No. 58-46199, gelled wheat starch, acrylamide and NN'-methylenebisacrylamide (crosslinking agent) were reacted to obtain a water-insoluble hydrophilic crosslinked polymer powder. . This hydrophilic cross-linked polymer contains fine particles of 105 microns or less @ 14.2%, and the water absorption rate measured using fI in the above measurement method was 92 seconds, indicating that water was absorbed uniformly. It was found that there was no water and the permeability was poor.

Comparative Example 2 Eri corn starch, acrylic acid, sodium acrylate 2 was added to the method of Example 8 of Japanese Patent Publication No. 5B-46199.
Process N,N'-methylenebisacrylamide was reacted to obtain a water-insoluble, hydrophilic crosslinked polymer powder.

This hydrophilic crosslinked polymer has fine particles of 105 microns or less.
It contained 9.8% i, the water absorption rate was 87 seconds, and the permeability was poor.

Comparative Example 3 The water absorption rate, permeability, and gelation time of the hydrophilic crosslinked polymer powder obtained in Comparative Example 2 from which fine particles of 106 microns or less were removed were measured, and the results are as shown in Table 1. Ta.

Comparative Example 4 200 parts of Normanhexane, 2 parts of sorbitan monostearate, 9 parts of acrylic acid, 28 parts of sodium acrylate and 40 parts of water were added to a Yotsuka round bottom flask and the mixture was heated at 20°C.
Stirring was performed for 0 minutes.

Next, nitrogen gas was blown into the mixture to remove dissolved oxygen, and then potassium persulfate α was added and the mixture was reacted at 60C for 8 hours. After the reaction, the product 17 was filtered and dried under reduced pressure at 60° C. for 8 hours to obtain a self-crosslinked powdery water-insoluble hydrophilic crosslinked polymer. This product contained fine particles of 105 microns or less (H4,611b), water absorption rate, permeability, and gelation time, and the results were as shown in Table 1.

Example 1 1 part of glycerin α was completely added to 100 parts of the powdered hydrophilic crosslinked polymer (water-absorbing resin) obtained in Comparative Example 1, and the mixture was mixed in a Nauta mixer for 80 minutes to produce a product almost the same as that of Comparative Example 1. A powdery water absorbent resin composition having a particle size distribution was obtained. This product shows an extremely excellent water absorption speed of 17 seconds,
Uniform penetration of water was achieved. The water absorption performance was equivalent to that without treatment.

Examples 2 to 5 In Example 1, in place of 1 part of glycerin α, the compounds listed in Table 1 were used to produce powder-like water absorbent powder having approximately the same particle size distribution as Comparative Example 1, using exactly the same method. A resin composition was obtained. As a result of measuring all of their water absorption rate, permeability, and gelation time, a significant improvement was observed as shown in the first person.

Example 6 100 parts of the powdered hydrophilic crosslinked polymer (water-absorbing resin) obtained in Comparative Example 2 and glycerin Bo having an average molecular weight of about 2600
/Po Random adduct 10 parts were mixed together to prepare a mass goo patch. By putting 1 part of this master hatch and 100 parts of the hydrophilic crosslinked polymer into a fully conical blender and mixing for 20 minutes, a powdery water-absorbing resin composition having a particle size distribution almost the same as that of Comparative Example 2 was obtained. Ta. As shown in Table 1, significant improvements were observed in the water absorption rate, permeability and gelation time of this product.

Example 7 A powdery water-absorbing resin composition was obtained in exactly the same manner as in Example 6, except that an EO adduct of polypropylene glycol having an average molecular weight of about 2,400 was used instead of the glycerin EO/PO random adduct.

As shown in Table 1, significant improvements were observed in the water absorption rate, permeability, and gelation time.

Example 8 Powdered water-insoluble/hydrophilic crosslinked polymer obtained in Comparative Example 4 (
While stirring 100 parts of water-absorbent resin with a ribbon mixer, 8 parts of ethylene glycol α was sprayed and mixed uniformly to obtain a powdery water-absorbent resin composition having approximately the same particle size distribution as Comparative Example 4. . As shown in Table 1, the water absorption rate, permeability and gelation time of this product were significantly improved.

Table 1

Claims (1)

[Scope of Claims] 1. The powdered water-insoluble water-absorbing resin (I), the di- to octahydric polyhydric alcohol and /lfC are composed of its oxyalkylene ether (II), and the amount of (II) is ( 1. A powdery water-insoluble water-absorbent resin composition with improved absorption rate, characterized in that the amount is 0.01 to 5 1 sl per the amount of I). 2. (I) is a water-soluble monomer and/or a monomer (A) that becomes water-soluble upon hydrolysis, a polysaccharide (B), and a crosslinking agent (C) as all essential components, and hydrolyzed as necessary. Claim 1
Compositions as described in Section.